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SA now experiencing half-year summers

12 October 2020 | Story Leonie Bolleurs | Photo Supplied

Although several international studies have used temperature metrics to statistically classify their seasonal divisions, a study in which Adriaan van der Walt was involved, would be the first known publication in a South African context using temperature as classification metric.

Gone are the days when we as South Africans would experience a three-month spring season, easing into summer, and then cooling off for three months before we hit winter.

Adriaan van der Walt, Lecturer in the Department of Geography at the University of the Free State (UFS), focuses his research on biometeorology (a specialist discipline exploring the role and climate change in physical and human environments) as well as climatology and geographic information systems.

He recently published an article: ‘Statistical classification of South African seasonal divisions on the basis of daily temperature data’ in the South African Journal of Science.

In this study, which Van der Walt undertook with Jennifer Fitchett, a colleague from the University of the Witwatersrand, data on daily maximum and minimum temperatures was collected from 35 meteorological stations of the South African Weather Service, covering the period between 1980 and 2015.

They went to great lengths to ensure that they had a complete set of data before presenting it to demonstrate seasonal brackets.

First for South Africa

Their statistical seasonal brackets indicate that South Africans now experience longer summers (from October to March), autumn in April and May, winter from June to August, and spring in September.

Although considerable work has been done using rainfall to determine seasonality in Southern Africa, Van der Walt believes that these methods did not work well as there are too many inconsistencies in this approach, as identified by Roffe et al. (2019, South African Geographical Journal). To make matters more complicated – as a semi-arid region, and with desert conditions along the west coast – some regions do not have enough rainfall to use as a classifier.

Temperature, on the other hand, worked well in this study. “Temperature, by contrast, is a continuous variable, and in Southern Africa has sufficient seasonal variation to allow for successful classification,” says Van der Walt.

He continues: “Although several international studies used temperature metrics to statistically classify their seasonal divisions, this study would be the first known publication in a South African context using temperature as classification metric.”

Van der Walt says what we understand as seasons largely relates to phenology – the appearance of blossoms in spring, the colouration and fall of leaves in autumn, and the migration of birds as a few examples. “These phenological shifts are more sensitive to temperature than other climatic variables.”

Seasonal brackets

According to Van der Walt, they believe that a clearly defined and communicated method should be used in defining seasons, rather than just assigning months to seasons.

“One of the most important arguments of our work is that one needs to critically consider breaks in seasons, rather than arbitrarily placing months into seasons, and so we welcome any alternate approaches,” he says.

A number of sectors apply the temperature-based division to their benefit. “For example, in the tourism sector it is becoming increasingly important to align advertising with the season most climatically suitable for tourism,” says Van der Walt.

Temperature-based division is also used to develop adaptive strategies to monitor seasonal changes in temperature under climate change. However, Van der Walt points out that each sector will have its own way of defining seasons. “Seasonal boundaries should nevertheless be clearly communicated with the logic behind them,” he says.

News Archive

New challenges for animal science discussed

2006-04-04

Some of the guests attending the congress were from the left Dr Heinz Meissner (honorary president of the South African Society for Animal Science (SASAS) and senior manager at the Animal Production Institute of the Agricultural Research Council), Mr Paul Bevan (President of SASAS) and Prof Magda Fourie (Vice-Rector: Academic Planning at the UFS).
Photo: Lacea Loader

New challenges for animal science discussed

The South African Society for Animal Science (SASAS) is presenting its 41st Congress at the University of the Free State’s (UFS) Main Campus in Bloemfontein.

The congress started yesterday and will run until Thursday 6 April 2006. The theme is New challenges for the animal science industries.

It is one of the largest congresses in the 45 years since SASAS was founded in 1961. Among the delegates 12 African countries are represented, with the biggest delegation from Kenya. Delegates are also from the United States of America, Iran, Turkey, Germany, the Netherlands and Portugal and African countries like Zimbabwe, Mozambique and Botswana.

“Many of our members play an important role in the training of animal scientists at universities. The congress is specifically industry orientated so that scientists can interact with farmers through the respective producer organisations,” said Prof HO de Waal, Chairperson of the organising committee and lecturer at the UFS Department of Animal, Wildlife and Grassland Sciences.

According to Dr Heinz Meissner, honorary president of SASAS and a senior manager at the Animal Production Institute of the Agricultural Research Council, the National Livestock Strategy (NLS) Plan clarifies the role and responsibility of the livestock sector.

“Through this strategy we need to focus on enhancing equitable access and participation in livestock agriculture, improve global competitiveness and profitability of the livestock sector and ensure that the ventures implemented do not over utilise our resources,” said Dr Meissner.

In her welcoming address, Prof Magda Fourie, Vice-Rector: Academic Planning at the UFS highlighted the related challenges that the UFS will be focusing on specifically over the next five years. “We have identified five strategic clusters that represent broad areas of excellence in research and post-graduate education. Two of these are food production, quality and safety for Africa and sustainable development,” she said.

“The food safety and security cluster will focus on the production of food in all its varieties within the African context, encompassing the entire value chain – from production to consumption and nutrition related issues. This would include a strong emphasis on sustainable production systems,” she said.

According to Prof Fourie the rural development cluster will engage in questions around the role of higher education in sustainable development. “One of the focus areas in this strategic cluster pertains to sustainable livelihoods. It refers to a way of approaching development that incorporates all aspects of human livelihoods and means by which people obtain them,” she said.

Prof Fourie said that the challenges we are facing such as food production can only be effectively addressed through collaborative efforts. “That is why it is important that collaboration takes place between different scientific disciplines, researchers, institutions and countries who are confronted with similar difficulties,” she said.

According to Prof de Waal the congress will give key role players a unique opportunity to present a profile of what they perceive an animal scientist should be and state their specific requirement regarding the animal sciences and its applications.

“In this way we can determine what the industry’s needs are and we can re-align our curriculum to suit these needs,” said Prof de Waal.

During the next two days, various areas of interest will be discussed. This includes ruminant and monogastric nutrition, animal physiology, beef, dairy, sheep and ostrich breeding and sustainable farming covering the range from commercial to the small-scale farming level.

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
4 April 2006

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